The enzymatic activity of AOC3 (amine oxidase, copper containing 3; vascular adhesion protein 1) has been described already in 1967 as a monoamine oxidase activity in the plasma of chronic liver disease patients (Gressner, A. M. et al., 1982, J. Clin. Chem. Clin. Biochem. 20: 509-514; McEwen, C. M., Jr. et al., 1967, J. Lab Clin. Med. 70: 36-47). AOC3 has two closely homologous genes in the human genome: AOC1 which corresponds to a diamine oxidase (Chassande, O. et al., 1994, J. Biol. Chem. 269: 14484-14489) and AOC2, a SSAO with a specific expression in the retina (Imamura, Y. et al., 1997, Genomics 40: 277-283). AOC4 is a sequence that does not lead to a functional gene product in humans due to an internal stop-codon (Schwelberger, H. G., 2007, J. Neural Transm. 114: 757-762).
The enzyme contains an oxidized 2,4,5-trihydroxy-phenalalanyl-quinone (TPQ) and a copper ion in the active side. This characteristic catalytic center classifies the semi-carbazide-sensitive amine oxidase (SSAO, copper-containing amine:oxygen oxido-reductase (deaminating)): The type II membrane protein belongs to the family of copper containing amine oxidases together with several other diamine and the lysyl oxidases. However the later enzymes can be distinguished from AOC3 in their preference for diamines and the low sensitivity towards semicarbazide inhibition (Dunkel, P. et al., 2008, Curr. Med. Chem. 15: 1827-1839). On the other hand monoamine oxidases contain the flavin adenine dinucleotide (FAD) cofactor in their reactive center like the monoamine oxidase A (MAO-A) and MAO-B and follow therefore a completely different reaction scheme.
AOC3 catalyzes a two-step reaction mechanism for the oxidative deamination of primary aliphatic and aromatic amines. In a first reaction the primary amine forms a Schiffbase with the TPQ aldehyde. This covalent bond is hydrolyzed, releasing the aldehyde product and a substituted TPQ residue in the active core. In the presence of oxygen, TPQ is oxidized under the formation of ammonia and peroxide with the help of the copper molecule (Mure, M. et al., 2002, Biochemistry 41: 9269-9278). Several substrates of AOC3 have been described, like the physiological amines methylamine, dopamine, or aminoacetone, whose products of oxidation have been associated to cardiovascular pathologies (Yu, P. H. et al., 1993, Diabetes 42: 594-603). Synthetic amines have been optimized for their turnover by AOC3 like benzylaminde derivates (Yraola, F. et al., 2006, J. Med. Chem. 49: 6197-6208), C-Naphthalen-1-methylamine (Marti, L. et al., 2004, J. Med. Chem. 47: 4865-4874) or luciferin derivates (Valley, M. P. et al., 2006, Anal. Biochem. 359: 238-246). The later substrate can be used for the sensitive detection of AOC3 activity in plasma, tissue or for biochemical characterization of the enzyme.
Under pathophysiological conditions of high AOC3 activity the aldehyde products are highly reactive, leading to advanced glycosylation end products (Mathys, K. C. et al., 2002, Biochem. Biophys. Res. Commun. 297: 863-869) which are regarded as markers and drivers of diabetes associated inflammatory mechanisms.
Further the byproduct hydrogen peroxide is sensed by the tissue as a messenger of inflammation. The intermediate is able to activate endothelium and is fostering the activation of leukocytes.
The binding and modification of Siglec-10 as a membrane bound substrate provides a mechanistic understanding of how the enzymatic reaction could trigger the leukocyte transmigration through activated endothelia. The binding of Siglec-10 to AOC3 was shown in several adhesion assays and led to increased hydrogen peroxide production (Kivi, E. et al., 2009, Blood 114: 5385-5392). Binding of activated leukocytes to the dimeric, extracellular AOC3 via the Siglec-10 generates a transient association to the activated endothelial. Therefore the rolling velocity of leukocytes is reduced, which increases the transmigration of leukocytes into the interstitium of inflamed tissues. Further, a conserved RGD-motif on the surface of AOC3 argues for its adhesive role: The deletion of this sequence reduced leukocyte recruitment (Salmi, M. et al., 2000, Circ. Res. 86: 1245-1251) probably via a lack of integrin β1 binding activity (Aspinall, A. I. et al., 2010, Hepatology 51: 2030-2039).
This finding correlates to the phenotype of AOC3 knock out mice, which exert a reduced leukocyte and lymphocyte transmigration capacity (Stolen, C. M. et al., 2005, Immunity. 22: 105-115) into lymphoid organs and adipose tissue (Bour, S. et al., 2009, Am. J. Pathol. 174: 1075-1083).
AOC3 activity can be found in most tissues and is mainly expressed in endothelial cells, smooth muscle cells and adipocytes (Boomsma, F. et al., 2000, Comp Biochem. Physiol C. Toxicol. Pharmacol. 126: 69-78; O'Sullivan, J. et al., 2004, Neurotoxicology 25: 303-315). In humans, in contrast to mice, AOC3 activity is constitutive in the liver sinusoideal endothelial cells (McNab, G. et al., 1996, Gastroenterology 110: 522-528) and mRNA expression is further upregulated under inflammatory conditions in this tissue (Lalor, P. F. et al., 2002, Immunol. Cell Biol. 80: 52-64); Bonder, C. S. et al., 2005, Immunity. 23: 153-163). AOC3 not only exists as a membrane protein, but can also be found as soluble plasma activity probably due to a metalloprotease mediated shedding process (Abella, A. et al., 2004, Diabetologia 47: 429-438); Boomsma, F. et al., 2005, Diabetologia 48: 1002-1007; Stolen, C. M. et al., 2004, Circ. Res. 95: 50-57)). Elevated levels of soluble AOC3 have been observed in diabetes (Li, H. Y. et al., 2009, Clin. Chim. Acta 404: 149-153), obesity (Meszaros, Z. et al., 1999, Metabolism 48: 113-117; Weiss, H. G. et al., 2003, Metabolism 52: 688-692), congestive heart failure (Boomsma, F. et al., 1997, Cardiovasc. Res. 33: 387-391), end-stage renal disease (Kurkijarvi, R. et al., 2001, Eur. J. Immunol. 31: 2876-2884) and inflammatory liver disease (Kurkijarvi, R. et al., 1998, J. Immunol. 161: 1549-1557). For the later, levels of AOC3 plasma activity have been correlated to liver fibrosis and serve as a predictor in patients with NAFLD (Weston, C. J. et al., 2011, J. Neural Transm. 118: 1055-1064). After transplantation of cirrhotic livers, high AOC3 plasma levels dropped drastically, which argues for the liver as the major source of plasma AOC3 activity under this pathological condition (Boomsma, F. et al., 2003, Biochim. Biophys. Acta 1647: 48-54).
The role of AOC3 in the activation of inflammation via peroxide generation and the recruitment of leukocytes to activated endothelium makes it an attractive target for the treatment of inflammatory components in several diseases. Therefore a variety of small molecular compounds and antibodies have been tested in different disease animal models. Amongst those, the inhibition of AOC3 showed beneficial effects in the models of melanoma and lymphoma cancer (Marttila-Ichihara, F. et al., 2010, J. Immunol. 184: 3164-3173), acute and chronic joint (Tabi, T. et al., 2013, J. Neural Transm. 120: 963-967) or lung (Foot, J. S. et al., 2013, J. Pharmacol. Exp. Ther. 347: 365-374) inflammation, diabetic macular edema (Inoue, T. et al., 2013, Bioorg. Med. Chem. 21: 1219-1233), kidney fibrosis (Wong, M. et al., 2014, Am. J. Physiol Renal Physiol 307: F908-F916), liver allograft rejection (Martelius, T. et al., 2004, Am. J. Pathol. 165: 1993-2001) and non-alcoholic liver disease.
The development of a selective, potent and well tolerated AOC3 inhibitor would therefore be beneficial for the treatment of the respective human diseases.
AOC3 inhibitors are known in the art, for example, the compounds disclosed in EP 2 695 881 corresponding to WO 2012/124696. The heteroaryl derivatives of the present invention may provide several advantages, such as enhanced potency, reduced plasma protein binding, improved CYP (cytochrome P450) enzyme profile and high metabolic stability, high chemical stability, improved tissue distribution, improved side effect profile and/or tolerability and in consequence low toxicity, reduced risk to cause adverse events or undesirable side effects, and enhanced solubility. The heteroaryl derivatives of the present invention exhibit increased metabolic stability, enabeling less frequent dosing and lower doses as compared to the corresponding phenyl analogues. Moreover, the heteroaryl derivatives of the present invention show reduced biliary clearance, which is expected to be impaired in patients with liver diseases (Clarke J. D. et. al J. Pharm. Exp. Ther. 348:452-458; Ferslew B. C. et al. Clin. Pharm. & Ther. Vol 97(4) XX), resulting in a better predictibitlity of the pharmacokinetics and assessment of safety margins in this patient population.
Aim of the Present Invention
The aim of the present invention is to provide new compounds, in particular new heteroaryl derivatives, which are active with regard to AOC3.
Another aim of the present invention is to provide new compounds, in particular new heteroaryl derivatives, which are active with regard to AOC3.
A further aim of the present invention is to provide new compounds, in particular new heteroaryl derivatives, which have an inhibitory effect on AOC3 in vitro and/or in vivo and possess suitable pharmacological and pharmacokinetic properties to use them as medicaments.
A further aim of the present invention is to provide new compounds, in particular new heteroaryl derivatives, which have an inhibitory effect on AOC3 in vitro and/or in vivo and possess suitable pharmacological and pharmacokinetic properties to use them as medicaments.
A further aim of the present invention is to provide effective AOC3 inhibitors, in particular for the treatment of various diseases, for example of NASH (non-alcoholic steatohepatitis), retinopathy and nephropathy.
Another aim of the present invention is to provide effective AOC3 inhibitors for the treatment of metabolic disorders such as NASH (non-alcoholic steatohepatitis), retinopathy and nephropathy.
A further aim of the present invention is to provide methods for treating a disease or condition mediated by the inhibition of AOC3 in a patient.
A further aim of the present invention is to provide a pharmaceutical composition comprising at least one compound according to the invention.
A further aim of the present invention is to provide a combination of at least one compound according to the invention with one or more additional therapeutic agents.
A further aim of the present invention is to provide methods for the synthesis of the new compounds, in particular heteroaryl derivatives.
A further aim of the present invention is to provide starting and/or intermediate compounds suitable in methods for the synthesis of the new compounds.
Further aims of the present invention become apparent to the one skilled in the art by the description hereinbefore and in the following and by the examples.
Object of the Invention
Within the scope of the present invention it has now surprisingly been found that the new compounds of general formula (I) as described hereinafter exhibit an inhibiting activity with regard to AOC3.
According to another aspect of the present invention it has been found that the new compounds of general formula (I) as described hereinafter exhibit an inhibiting activity with regard to AOC3.
In a first aspect the present invention provides a compound of general formula

wherein
X1 is selected from the group X1-G1 consisting of: N and CH;
X2 is selected from the group X2-G1 consisting of: N and CF;
whith the proviso that at least one of X1 and X2 is N;
A is selected from the group A-G1 consisting of:
    R4 is selected from the group R4-G1 consisting of: azetidinyl, pyrrolidinyl, piperidinyl, piperazinyl, morpholinyl, tetrahydropyranyl, oxazolidinyl, C3-8-cycloalkyl, phenyl, pyridinyl, pyrazinyl, pyridazinyl, pyrimidinyl, [1,3,5]triazinyl, triazolyl, thiazolyl, imidazo[1,2-a]pyridin-2-yl, 2,3-dihydro-1H-isoindolyl, oxazolyl and oxadiazolyl,            wherein each R4 is optionally substituted with one or more groups independently of each other selected from a group consisting of halogen, OH, CO2H, CN, CF3, C1-3-alkyl, C3-6-cycloalkyl, C1-3-alkyl-O—, (RN)2N—, C1-3-alkyl-C(═O)—, C1-4-alkyl-O—C(═O)—, (RN)2N—C(═O)—, (RN)2N—C1-3-alkyl-, C3-6-cycloalkyl-C1-3-alkyl-O—, C1-3-alkyl-SO2—, (RN)2N—SO2—, 2-oxo-pyrrolidinyl and C1-3-alkyl-C(═O)—(RN)N—C1-3-alkyl-; and        wherein a —CH2-group of the pyrrolidinyl, 2,3-dihydro-1H-isoindolyl, oxazolidinyl, piperidinyl or piperazinyl group of R4 is optionally replaced with a —C(═O)—, —S(═O)— or —S(═O)2— group;            RN is selected from the group R4-G1 consisting of: H and C1-4-alkyl, wherein, if several RN groups are present, they may be indentical or different from one another;    R5 is selected from the group R5-G1 consisting of: CN and OH; or, R4 and R5 groups together with the carbon atom, to which they are attached, may form the following group:

wherein each of the above-mentioned alkyl and —O-alkyl groups may be linear or branched and are optionally substituted by one or more F;
a tautomer or stereoisomers thereof,
or a salt thereof,
or a solvate or hydrate thereof.
In a further aspect the present invention relates to processes for preparing a compound of general formula (I) and to new intermediate compounds in these processes.
A further aspect of the invention relates to a salt of the compounds of general formula (I) according to this invention, in particular to a pharmaceutically acceptable salt thereof.
In a further aspect this invention relates to a pharmaceutical composition, comprising one or more compounds of general formula (I) or one or more pharmaceutically acceptable salts thereof according to the invention, optionally together with one or more inert carriers and/or diluents.
In a further aspect this invention relates to a method for treating diseases or conditions which are mediated by inhibiting the activity of AOC3 in a patient in need thereof characterized in that a compound of general formula (I) or a pharmaceutically acceptable salt thereof is administered to the patient.
According to another aspect of the invention, there is provided a method for treating NASH (non-alcoholic steatohepatitis), retinopathy or nephropathy in a patient in need thereof characterized in that a compound of general formula (I) or a pharmaceutically acceptable salt thereof is administered to the patient.
According to another aspect of the invention, there is provided the use of a compound of the general formula (I) or a pharmaceutically acceptable salt thereof for the manufacture of a medicament for a therapeutic method as described above or hereinafter.
According to another aspect of the invention, there is provided a compound of the general formula (I) or a pharmaceutically acceptable salt thereof for use in a therapeutic method as described above or hereinafter.
In a further aspect this invention relates to a method for treating a disease or condition mediated by the inhibition of AOC3 in a patient that includes the step of administering to the patient in need of such treatment a therapeutically effective amount of a compound of the general formula (I) or a pharmaceutically acceptable salt thereof in combination with a therapeutically effective amount of one or more additional therapeutic agents.
In a further aspect this invention relates to a use of a compound of the general formula (I) or a pharmaceutically acceptable salt thereof in combination with one or more additional therapeutic agents for the treatment or prevention of diseases or conditions which are mediated by the inhibition of AOC3.
In a further aspect this invention relates to a pharmaceutical composition which comprises a compound according to general formula (I) or a pharmaceutically acceptable salt thereof and one or more additional therapeutic agents, optionally together with one or more inert carriers and/or diluents.
Other aspects of the invention become apparent to the one skilled in the art from the specification and the experimental part as described hereinbefore and hereinafter.